CCEP N1 latency increased with distance in 13 STReEF patients; this sample did not determine an age effect

In 8,344 expert-checked cortico-cortical evoked potential responses from 13 STReEF patients (5 ECoG, 8 SEEG; ages 10–50), N1 latency increased with Euclidean distance in every patient (mean within-patient Spearman rho = 0.42, 95% bootstrap CI 0.31–0.53; exact sign-flip p = 0.00024, Holm p = 0.00049). The mean latency slope was 0.61 ms/mm, with an intercept of 23.5 ms. The distance association remained in SEEG patients and after excluding contacts less than 13 mm away. The age association with median latency was rho = −0.33 (p = 0.26; Holm p = 0.26), so this 13-patient sample does not determine an age effect. Age associations with latency at 30 mm, apparent speed, and slope were also not significant. Older patients had shorter response distances, which can shorten median latency without a speed change. Contacts on the same electrode as stimulation had 4.4 ms shorter latency at the same distance (p = 0.0034), an effect absent at distances of at least 13 mm. Inference is at the patient level. Age and recording type are partly confounded; Euclidean distance is not fiber length; latency includes distance-independent delays; and patients may overlap with a previously reported cohort. N1 peaks were checked by the dataset authors and were not redetected from raw recordings.

cortico-cortical evoked potentials · N1 latency · single-pulse electrical stimulation · intracranial EEG · Euclidean distance · STReEF